JPH1175067A - Image processing unit and its method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image processing unit and its method in which fluctuation in short and long-term image density and gradation reproducibility is systematically corrected by forming a copy image through the operation of an image forming device single body and forming a print image based on image data fed from an external device. SOLUTION: A test print 1 is generated (S101), a correction coefficient Ka of a contrast potential for image forming is optimized by density information obtained in the step S102 (S103), and a grid potential and a development bias potential are set so as to obtain the contrast potential (S104). A test print 2 is generated (S105), a relation between a laser output and density is obtained based on density information obtained in the step 106 (S107) to set a gamma conversion characteristic (S108).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus and method, and more particularly to an image processing apparatus and method for processing an image sent from an external device such as a host computer and an image read from a document. is there.

[0002]

2. Description of the Related Art There is an image forming system comprising a controller which receives image data from a host computer and sends it to an image forming apparatus, and an image forming apparatus which forms an image based on the image data sent from the controller.
For example, an image forming system in which various controllers are combined with a CLC500 (registered trademark) color copying machine manufactured by Canon as an image forming apparatus has been commercialized. This color copier has a plurality of output color components C (Cyan), M (Magenta), Y (Yello
This is a laser beam type color electrophotographic printer that forms images sequentially for w) and K (Black), and by controlling the emission of the laser beam with a pulse width modulated signal according to the image signal, it is possible to express halftone Has been realized.

In the above-described image forming apparatus, a predetermined pattern is formed on an image carrier or a recording medium, and the density of the predetermined pattern is read to perform density correction and gradation correction. Techniques for stabilizing image quality are known.

[0004]

However, the above technique has the following problems.

[0005] An image (hereinafter referred to as a "copy image") in which a document is read and output by a color copier alone, which is an image forming apparatus, and an image output (hereinafter referred to as a "print image") based on image data sent from a controller. ") Are not standardized in terms of density and reproducibility of gradation.

Although there is calibration for adjusting the density and gradation reproducibility of a printed image using an expensive densitometer, calibration using a reader scanner attached to a color copying machine has not been performed. .

On the other hand, variations in image density and gradation reproducibility
There are short-term fluctuations caused by fluctuations in the device environment, and long-term fluctuations caused by the aging of the photoconductor and developer.To unify the density and gradation reproducibility of copy images and print images, Needs to be corrected in accordance with these various fluctuations.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and is intended to reduce the short-term and long-term fluctuations in image density and gradation reproducibility by forming a copy image by operating the image forming apparatus alone, and It is an object of the present invention to provide an image processing apparatus and method capable of uniformly correcting a print image based on image data sent from an external device.

It is another object of the present invention to provide an image processing apparatus and method capable of performing image adjustment suitable for an image forming system at low cost by using image reading means of the image forming apparatus. .

It is another object of the present invention to provide an image processing apparatus and method capable of performing image adjustment suitable for a connected image forming apparatus.

[0011]

The present invention has the following configuration as one means for achieving the above object.

[0012] An image processing apparatus according to the present invention comprises a first generating means for generating a first image signal from a document image, and a second generating means for generating a second image signal from image data described in a page description language. Generating means, correcting means for correcting the first or second image signal, forming means for forming a visible image on a recording medium based on the image signal corrected by the correcting means, A first setting unit configured to set a correction process of the correction unit and an image forming condition of the forming unit in image formation based on the first image signal based on an image signal generated by the unit; A second setting unit that sets a correction process of the correction unit and an image forming condition of the forming unit in image formation based on the second image signal based on the image signal generated by the unit. It is characterized in.

Preferably, the first and second setting means include a density of the first pattern based on an image signal generated by the first generating means from the first pattern formed by the forming means. Detecting information, setting image forming conditions of the forming unit based on the detected density information of the first pattern, and generating the image by the first generating unit from the second pattern formed by the forming unit. The density information of the second pattern is detected based on the detected image signal, and correction processing of the correction unit is set based on the detected density information of the second pattern.

[0014] Further, input means for inputting image data expressed in a page description language, correction means for performing correction processing on the image data using correction data to generate raster data, and outputting the raster data to a printer And output means for outputting reference patch data indicating a reference patch to the printer, inputting patch detection data indicating an image formed based on the reference patch data from the printer, and generating the correction data. It is characterized by having.

An image processing apparatus connected to a color copying machine having a calibration processing mode for a color copy mode and a calibration processing mode for a color print mode, wherein the image processing apparatus is configured to calibrate the color copying machine. And outputting means for outputting an instruction command for instructing execution of the application process.

An image processing method according to the present invention includes a first generating step of generating a first image signal from a document image using image reading means, and a first correcting step of correcting the first image signal. A second generation step of generating a second image signal from image data described in a page description language, a second correction step of correcting the second image signal, and the first or second A forming step of forming a visible image on a recording medium based on the image signal corrected in the correcting step, and the first step in forming an image based on the first image signal based on an image signal generated by a pattern generating unit. A first setting step of setting a correction process of a correction step and an image forming condition of the forming step,
Based on an image signal generated from image data described in a page description language, setting a correction process of the second correction step and an image formation condition of the formation step in image formation based on the second image signal. And two setting steps.

Preferably, the first and second setting steps include detecting density information of the first pattern based on an image signal generated by the image reading means from the first pattern formed in the forming step. Setting image forming conditions in the forming step based on the detected density information of the first pattern, and based on an image signal generated by the image reading unit from the second pattern formed in the forming step; The density information of the second pattern is detected, and the correction processing of the first or second correction step is set based on the detected density information of the second pattern.

An image processing apparatus for inputting image data expressed in a page description language, performing correction processing on the image data using correction data to generate raster data, and outputting the raster data to a printer. A processing method, wherein reference patch data indicating a reference patch is output to the printer, patch detection data indicating an image formed based on the reference patch data is input from the printer, and the correction is performed based on the patch detection data. It is characterized by creating data.

An image processing method for an image processing apparatus connected to a color copying machine having a calibration processing mode for a color copy mode and a calibration processing mode for a color print mode, the method comprising: And outputting an instruction command for instructing the execution of the calibration process.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an image processing apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings.

[0021]

[First Embodiment] [Overview of System] FIG. 1 is an overview diagram showing an example of the configuration of an image processing system according to an embodiment of the present invention, wherein 101 is a host computer, 102 is a controller, 10
3 is an image forming apparatus.

The image forming apparatus 103 performs color copying of a document image placed on a document table,
And outputs a color image based on the image data sent from the host computer 101.

On the host computer 101, a so-called DTP (DTP
esk Top Publishing) application software is running and various documents and figures are created and edited. The host computer 101 converts a created document or figure into a page description language (PD).
The data is converted into the data described in L) (hereinafter referred to as “PDL data”), and the PDL data is sent to the controller 102 via the connection cable 243.

The controller 102 is connected to the host computer 1
Performs raster image processing (RIP) for translating and rasterizing the PDL data sent from 01. The image signal obtained by this RIP is sent to the image forming apparatus 103 via the connection cable 242, and the image is output.

[Overview of Image Forming Apparatus] FIG.
FIG. 11 is an overview diagram showing a configuration example of a device 03.

A case where a document image is copied will be described. Reference numeral 201 denotes a platen glass, a document 2 from which an image is to be read.
02 is put. The document 202 is irradiated with light by a lamp 203, and reflected light from the document 202 is guided to a CCD 208 as a line sensor by an optical system 207 via mirrors 204, 205 and 206, and an image is formed on the CCD 208. Mirror 204 and lamp 2
03 including the mirror unit 210, the speed v
The mirror unit 211 including the mirrors 205 and 206 is mechanically moved at a speed of 1/2 v by the motor 209, so that the entire surface of the document 202 is scanned.

An image processing unit 212 processes an image signal output from the CCD 208, temporarily stores the processed image signal in an image memory, and outputs the image signal held at a predetermined timing as a print signal. The print signal output from the image processing unit 212 is sent to a laser driving unit 1006 described below, and drives four semiconductor laser elements (not shown).

A polygon mirror 213 reflects four laser beams output from four semiconductor laser elements,
One of them is a photosensitive drum 2 via mirrors 214, 215 and 216.
Scan 17 The other laser beams are
8, 219, 220, the photosensitive drum 221 is moved to mirrors 222, 223,
The photosensitive drum 225 is scanned via 224, and the photosensitive drum 229 is scanned via mirrors 226, 227 and 228.

Reference numeral 230 denotes a developing unit for supplying yellow toner, and develops a latent image formed on the photosensitive drum 217 by scanning with a laser beam with toner to form a yellow toner image. Similarly, a developing device 23 for supplying magenta toner
1. The developing devices 232 for supplying cyan toner and the developing device 233 for supplying black toner develop latent images formed on the photosensitive drums 221, 225 and 229 by toner scanning with laser beams.

The recording paper supplied from one of the recording paper cassettes 234 and 235 and the manual feed tray 236 is adsorbed on the transfer belt 238 via the registration roller 237 and is conveyed. A toner image of each color is formed on each photosensitive drum in synchronization with the supply timing of the recording paper.
The toner images of the four colors CK are transferred in an overlapping manner, and a full-color output image can be obtained. The recording paper onto which the toner image has been transferred is separated from the transfer belt 238, conveyed by the conveyance belt 239 to the fixing device 240, where the toner image is fixed, and discharged to the paper discharge tray 241.

On the other hand, when outputting an image based on the image data sent from the host computer 101 via the controller 102, the image data is input to the image processing unit 212 via the interface cable 242, and An image is formed as in the case of the operation.

The four photosensitive drums are arranged at regular intervals at a distance d, and the recording paper is conveyed by the transfer belt 238 at a constant speed v '. Accordingly, the four semiconductor laser elements are driven with a delay of time d / v ', thereby synchronizing the formation and transfer timing of the toner image.

[Copier Operation] In the system according to the present embodiment, there are an operation as a single copier and an operation as a system including the controller 102. The switching of these operations, and the operating conditions such as the number of prints and the recording paper size can be set from the operation panel 300d of the image forming apparatus 103 or from the host computer 101. First, the operation of the copier alone (hereinafter referred to as "copier operation") will be described.

In the case of a copying machine operation, as shown in FIG.
The image signal output from 208 is converted into an A / D converter 301, an input masking unit 302, and a LOG conversion unit (brightness / density conversion unit) 304.
After being compressed by the compression circuit 305, the data is written into the memory 306. Further, a character / line image determination signal TEXT indicating a determination result of the image area determination unit 303 for determining a character and a line image area is also written in the memory 108 after being compressed by the compression circuit 305.

The compressed data read from the memory 108 is
The data is decompressed by a decompression circuit 307 and sent to the subsequent stage in accordance with the image forming timing of the printer unit, and the masking / UCR unit 308
As a result, a masking process and a UCR process for matching the spectral sensitivity characteristics of the toner are performed to obtain a YMCK signal. Y
The MCK image signal is further subjected to processing such as edge enhancement and smoothing by the spatial filter 311 and the γ correction unit 31
2 performs gamma processing to match the printer characteristics. The CMYK data matched with the printer characteristics is converted into a pulse signal for driving the semiconductor laser element by the PWM circuit 313 and sent to a laser driver (not shown).

FIG. 4 is a timing chart showing the timing of writing and reading image data in the memory 108. The compressed image data is written into the memory 108 at a timing 1101, and the timings 1102, 1103, 1104 and 1105 are written.
Is read and decompressed. Note that timings 1102, 1103,
The interval between 1104 and 1105 is the time d '/ v described above.

The operation of the image forming apparatus 103 is performed in the RAM 303c.
Is used as a work memory, and is controlled by a CPU 300a that executes a control program and an image processing program stored in a ROM 300b.

[Print Operation] In the system operation including the controller 102, the image forming apparatus 103 includes the controller 1
There are two operations, a print operation for outputting an image based on the image data sent from the printer 02 and a scan operation for outputting image data to the controller 102. First, the printing operation will be described.

The PDL data is sent from the host computer 101 to the CPU 351 of the controller 102. The CPU 351 stores the received PDL data in the hard disk 354. When the entire job sent from the computer 101 has been stored in the hard disk 354, the CPU 351 starts translating the PDL data stored in the hard disk 354. The translated PDL data is rasterized into full-color image data in print order, and stored as a raster image in the DRAM 352. Note that the rasterized image data is image data that has been color-separated into four colors of YMCK in accordance with the characteristics of the image forming apparatus 103. In addition, the characters
The line data determination signal TEXT is also written to the DRAM 352, and the image data and the determination signal TEXT are read from the DRAM 352 at the same timing as the write / read timing of the memory 108 shown in FIG. Is sent to the image forming apparatus 103.

When the PDL data cannot be stored in the hard disk 354 at one time or when high-speed printing is required, the job is divided and the divided PDL data is transferred in units of job. You may. Further, although rasterization is performed in page units, if the storage capacity of the DRAM 352 is sufficiently ensured, all of one job is rasterized. If the storage capacity is not sufficient or if the first print speed is required, preparation for printing is sequentially performed in the order of rasterization, and image data is sent to the image forming apparatus 103 via the external interface 353.

The CPU 351a executes the control program and the processing program stored in the ROM 351b using the RAM 351c as a work memory to interpret and rasterize the PDL data, and further performs the same masking processing and UCR as the masking / UCR unit 308. Perform processing such as processing.

On the other hand, the image data and the determination signal TEXT sent to the external interface 309 of the image forming apparatus 103 are
Selected by the selector 310 controlled by the PU 300a,
It is sent to the processing blocks after the spatial filter 311. The selection operation of the selector 310 is performed by the external interface 353
And 309 via the CPUs 351a and 300a.

[Scan Operation] Next, the scan operation will be described.

The CPU 351a of the controller 102 communicates with the CPU 300a of the image forming apparatus 103 to scan the original 202 and
Scan the 02 image. Then, for example, 8-bit RGB image data that has passed through the input masking 302 is written to the DRAM 352 as a raster image via the external interfaces 309 and 353. The writing timing of the image data is the same as the timing indicated by reference numeral 1101 in FIG. Of course, if necessary, image data can be transferred from the DRAM 352 to the hard disk 354, or the image data can be sent to the host computer 101 and displayed on its display.

[Details of Image Processing Unit]
Details of each part of 212 will be described.

The analog image signal output from the CCD sensor 208 is subjected to gain adjustment and offset adjustment in an A / D converter 301, and then A / D converted to, for example, a digital image signal R0 of 8 bits each for RGB. G0, B0. Thereafter, a known shading correction using a read signal of the reference white plate is performed on the digital image signals R0, G0, B0 by a shading correction circuit (not shown). Further, since the line sensors of each color of the CCD 208 are arranged at a predetermined distance from each other, the spatial deviation in the sub-scanning direction is corrected by a line delay adjustment circuit (not shown) by the digital image signals R0, G0, B0.
It is applied to

The input masking unit 302 converts the color space of the image signals R0, G0, and B0 determined by the spectral characteristics of the R, G, and B filters of the CCD 208 into, for example, NT
Convert to SC standard color space. Where Cij (i = 1,2,3 j = 1,
(2, 3) are device-specific constants taking into account various characteristics such as the sensitivity characteristics of the CCD 208 and the spectral characteristics of the lamp 203.

The LOG conversion unit 304 is configured by a look-up table (LUT) such as a RAM, and converts the RGB luminance signal into C1, M1, and Y1 density signals by the following equation. Where α is a constant,
The base of the logarithm is 10. C1 = -α × log (R / 255) M1 = -α × log (G / 255)… (2) Y1 = -α × log (B / 255)

The compression circuit 305 compresses the YMC image signal and the determination signal TEXT to reduce the amount of information or the redundancy of the information, and then stores them in the memory 108. The expansion circuit 307 is a memory
Data read from 108 is converted to YMC image signal and judgment signal
Expand to TEXT. Note that image compression methods include lossless compression run-length coding, Huffman coding, arithmetic coding, Lempel-Ziv (LZ), and discrete cosine transform (DCT).
For example, JPEG encoding of lossy compression using, for example, can be used.

The output masking / UCR section 308 receives the input.
The C1, M1, and Y1 image signals are corrected according to the spectral sensitivity characteristics of the toner using the following equation, and the YMCK corresponding to the toner color is corrected.
Convert to image signal. In this conversion, the decision signal TE
The black generation operation and the masking operation are switched according to XT. That is, when TEXT = '0', that is, in the photograph mode in which the gradation is important, a K1 signal which is a black signal is generated by the equation (5), and T
EXT = '1' (6)
The K1 signal is generated by the equation. Note that a ^ b represents a raised to the power of b. MIN = min (Y, M, C)… (3) MAX = max (Y, M, C)… (4) K1 = MIN… (5) K1 = MIN ・ (MIN / MAX) + MIN ・ (1- MIN / MAX) (MIN / 255) ^ 2… (6)

The masking operation is as shown in equation (7) in the photograph mode with TEXT = '0', and as in equation (8) in the character mode with TEXT = '1'. Where the matrix coefficients aij (i =
1, ..., 4j = 1, ..., 8) and bij (i = 1, ..., 4j = 1, ..., 8) have different values.

Image area determining section 303 for detecting a character / line drawing area
ND signal generator 314 and TEXT / LI
The NE detector 315 determines whether each pixel of the image data is a pixel constituting a character or a line drawing, and generates a determination signal TEXT indicating the determination result. It should be noted that a determination signal TEXT is generated such that the pixel becomes "1" when the pixel forms a character or a line drawing, and "0" otherwise.

The selector 310 is controlled so as to select the image signal output from the masking / UCR unit 308 in the case of a copying machine operation, and to select the image signal from the controller 102 in the case of a printing operation. The image signal selected by the selector 310 is subjected to edge enhancement (sharpness) or smoothing by the spatial filter 311, and is subjected to gamma correction according to the characteristics of the printer unit by the LUT of the γ correction unit 312, and then to the PWM circuit 313. Is input to

[Image Area Determining Unit] The ND signal generator 314 generates an ND signal, which is a brightness signal in consideration of human luminous sensitivity characteristics, from the RGB image signal by the product-sum operation shown in the following equation. However, d1, d2, and d3 are constants in consideration of human luminosity characteristics.

The TEXT / LINE detector 315 is means for determining the pixels constituting the character and the line drawing. The TEXT / LINE detector 315 determines the pixels constituting the character and the line drawing based on the brightness signal ND, and generates a TEXT signal. Since this type of circuit is already known, a detailed description thereof will be omitted.

FIG. 5 is a diagram for explaining the judgment signal TEXT.
01 indicates an original 202 or an example of an image to be printed out. That is, in the image 402, only the character / line drawing portion becomes black, and the other portions become white. Image 402
In the image 403 in which a part of is enlarged, pixels indicated by black circles “●” 404 are pixels constituting a character or a line drawing,
The corresponding TEXT signal becomes '1'. On the other hand, white circle "○" 405
Are pixels other than characters and line drawings, and the corresponding TEXT signal is '0'.

[PWM Circuit] FIG. 6 is a block diagram showing a configuration example of the PWM circuit 313. However, the configuration in FIG. 6 is for one color, and the configuration in FIG. 6 is necessary for each color of YMCK.

Reference numeral 601 denotes a D / A converter, which converts an input digital image signal into an analog signal and sends it to a comparator 605. Reference numeral 602 denotes an image triangular wave generator that places importance on gradation, and generates a triangular wave having one pixel cycle. Reference numeral 603 denotes a triangular wave generator for an image in which resolution is emphasized, and generates a triangular wave having a period of two pixels. 604 is a selector, and a determination signal TEX
One of the two triangular waves is selected according to T and sent to the comparator 605.

According to the above configuration, the judgment signal TEXT becomes "1".
In an image area forming a character or a line drawing, the comparator 605 compares an image triangular wave output from the triangular wave generator 603 with an emphasis on resolution and an analog signal. In an image area other than a character or a line drawing, the comparator 605 compares an image triangular wave output from the triangular wave generator 602 with an emphasis on gradation and an analog signal. The output of comparator 605 is
A PWM signal is input to a laser driver 606 that drives the semiconductor laser element 607.

FIG. 7 is a diagram showing the state of pulse width modulation.
The upper part shows the state of pulse width modulation in an image where importance is placed on gradation. An output 801 of the D / A converter 601 is compared with a triangular wave 802 having a two-pixel cycle, and a PWM signal 803 is obtained. On the other hand, the lower part of FIG. 7 shows a state of pulse width modulation in an image where importance is placed on resolution. 804 is the D / A converter 60
The output 804 of 1 is compared with the triangular wave 805 of one pixel cycle, and P
A WM signal 806 is obtained.

In practice, the PWM signals 803 and 806 are adaptively switched and output according to the determination signal TEXT, so that a preferable image formation according to the image area characteristics of the image to be formed is performed.

[Image Forming Unit] The PWM signal output from the comparator 605 in FIG.
The semiconductor laser element 607 is driven to output a laser beam. The laser beam is scanned by the polygon scanner 213 to form a latent image on each photosensitive drum.

As described above, since the image forming units corresponding to the respective YMCKs are substantially the same, only the Y image forming unit will be described below with reference to FIG. 7, and the description of the image forming units for other colors will be omitted.

Around the photosensitive drum 217 in the Y image forming section,
A primary charger 701 for charging the surface of the photosensitive drum 217 to a predetermined potential to form an electrostatic latent image, a developing device 230 for developing the latent image on the photosensitive drum 217 into a toner image, and discharging from the back surface of the transfer belt 238. The transfer blade 7 for transferring the toner image on the photosensitive drum 217 to the recording paper on the transfer belt 238.
02, Cleaner 7 to clean the surface of the photosensitive drum 217 after transfer
03. There is an auxiliary charger 704 and a pre-exposure lamp 705 for erasing residual charges on the surface of the photosensitive drum 217 after transfer.

The recording paper on which the Y toner image has been transferred is
The toner images are conveyed by the transfer belt 238, and the respective toner images are transferred by the respective image forming units in the order of M, C, and K, and the four color toner images are superimposed. The recording paper that has passed through the K image forming unit is discharged from the transfer belt 238 after being discharged by a discharging charger 261 (see FIG. 2) in order to facilitate separation from the transfer belt 238. The recording paper separated from the transfer belt 238 is charged by a pre-fixing charger 262 (see FIG. 2) in order to supplement the toner attraction force and prevent image disturbance,
The fixing device 240 (see FIG. 2) fixes the toner image.

On the other hand, the transfer belt 238 from which the recording paper has been separated
Is removed by a transfer belt charge removal charger 263 (see FIG. 2), further cleaned by a belt cleaner (not shown), and preparations are made to adsorb recording paper again.

[First Automatic Gradation Correction] In this embodiment, two types of density and gradation control (hereinafter referred to as "automatic gradation correction") are used to obtain image density and gradation stability when forming a full-color image. "). First, the first control in the first automatic gradation correction will be described.

FIG. 9 is a flowchart showing a first control example in the first automatic gradation correction, which is executed by the CPU 300a. 10A to 10D are display examples of the operation panel 300d of the image forming apparatus 103.

When the "automatic gradation correction" key (not shown) on the operation panel 300d is pressed, the first control starts. The screen shown in FIG. 10A is displayed on the operation panel 300d, and when the “test print 1” key is pressed, the step shown in FIG. 9 is performed.
In S101, a test print 1 is output according to the above-described image forming process. At this time, the presence or absence of the recording paper necessary to form the test print 1 is determined by the CPU 300a,
If there is no recording paper, a warning is displayed. When forming the test print 1, a standard contrast potential (described later) according to the environmental conditions of the image forming apparatus 103 is used as an initial value. Test pattern 1 has a YMC
Band pattern 1001 consisting of halftone density of four colors of K and YMC
K includes patch patterns 1002, 1003, 1004, and 1005 each of which is composed of the maximum density patch (density signal level 255).

Next, the screen shown in FIG. 10B is displayed on the operation panel 300d, the output test print 1 is placed on the platen glass 201, and the "read" key is pressed. The reading of 1 is started. The RGB data of each pattern of the test print 1 is converted into an optical density by the LUT of the LOG conversion unit 304. LOG
In the LUT of the conversion unit 304, a coefficient calculated using Expression (2) is set in advance. That is, the correction coefficient α in the equation (2) is adjusted so as to obtain the optical density.

Next, a method for correcting the maximum density from the density information thus obtained will be described. FIG. 12A is a diagram showing the relationship between the relative value of the surface potential of the photosensitive drum (hereinafter, simply referred to as “surface potential”) and the density information obtained above.

The photosensitive drum which is primarily charged by the contrast potential used for forming the test print 1, ie, the developing bias potential, is scanned by a laser beam output from a semiconductor laser device driven at the maximum light emission level. When the surface potential difference of the drum is a and the maximum density at that time is Da, in a region near the maximum density, the density value with respect to the surface potential of the photosensitive drum has a linear relationship as shown by a solid line L in FIG. 12A. That is the most.
However, in the two-component developing system, when the toner density in the developing device changes and decreases, the density value with respect to the surface potential of the photosensitive drum becomes non-linear in a region near the maximum density as shown by a broken line N in FIG. 12A. May be. Therefore, in consideration of a margin of 0.1 with respect to the final target value 1.6 of the maximum density, the control amount is determined by setting 1.7 as the control target value of the maximum density.

The contrast potential b is obtained using the following equation. However, ka is a correction coefficient, and it is preferable to optimize Ka in step S103 according to the type of the developing method. b = (a + ka) × 1.7 / Da… (10)

Next, a method of obtaining the grid potential and the developing bias potential from the contrast potential b will be briefly described. FIG. 12B is a diagram illustrating a relationship example between the grid potential and the surface potential of the photosensitive drum.

The grid potential Vg is set to −300 V, the surface potential Vd when the photosensitive drum is scanned with the laser beam with the light emission level of the semiconductor laser element minimized, and the light emission level of the semiconductor laser element maximized. The surface potential Vl when the drum was scanned with the laser beam was measured using a surface potentiometer 70.
Measure at 8 (see Figure 8). Similarly, set the grid potential Vg to -7
Measure Vd and Vl when set to 00V. Got -30
The relationship between the grid potential Vg and the surface potential of the photosensitive drum is obtained by interpolating and extrapolating between the data of 0 V and -700 V. The control for obtaining the potential data is called “potential measurement control”.

Then, a predetermined potential difference is set so that the so-called fogging toner which adheres to the image from the obtained Vd does not occur.
Vback (for example, 150 V) is provided to set the developing bias Vdc. The contrast potential Vb is a difference voltage between the developing biases Vdc and Vl. As Vb increases, the maximum density can be increased.
The grid potential Vg for obtaining the obtained contrast potential Vb and the developing bias potential Vdc can be obtained from FIG. 12B.

In this embodiment, in step S104, the contrast potential Vb is determined so as to obtain the target value 1.7 of the maximum density as described above, and the grid potential Vg and the developing bias potential Vdc are determined so as to obtain the contrast potential Vb. Set.

Next, the role of the γ correction section 312 and the method of correcting the gradation will be described. FIG. 13 is a characteristic conversion chart showing an example of the density reproduction characteristic.

A first area I shown in FIG. 13 shows image reading characteristics for converting a document image into a density signal, a second area II shows a conversion characteristic of a gamma correction unit 312 for performing gamma correction on a density signal, The third area III indicates the gamma characteristic of the printer indicating the relationship between the laser output signal and the image density, and the fourth area IV indicates the relationship between the document density and the output image density. That is, the fourth area
The characteristic of IV indicates the overall gradation characteristic in the image forming apparatus 103. In the present embodiment, digital signals of 8 bits for each color are handled, so that the number of gradations for each color is 256.

Further, the gamma characteristic of the printer in the third area III is shown by a solid line J by the maximum density control for setting the maximum density target value higher. If the control for increasing the target value of the maximum density is not performed, the gamma characteristic of the printer may not reach the target density of 1.6 as indicated by the solid line H. In the case of a printer exhibiting the characteristics of the solid line H, no matter how the gamma correction unit 312 is set,
Since 12 does not have the ability to increase the maximum concentration,
Concentrations between concentrations DH and 1.6 are not reproducible.

In the image forming apparatus 103, in order to make the characteristic of the fourth region IV linear, the gamma characteristic of the third region III is curved and corrected by the gamma conversion characteristic of the second region II. I have. The gamma conversion characteristic given to the gamma correction unit 312 can be easily obtained simply by reversing the input / output relationship of the gamma characteristic of the printer in the third area III.

Next, in step S105, a test print 2 is output according to the display on the operation panel 300d shown in FIG. 10C. When outputting test print 2, γ correction unit 3
The gamma correction function of 12 is stopped.

Test print 2 has a Y
Patch groups 1101 and 1105, M patch groups 1102 and 1106, C
The patch groups 1103 and 1107, and the K patch groups 1104 and 1108 are composed of gradation patches for 64 tones in 4 rows and 16 columns. By intensively assigning the low-density area of the 256 gradations to these 64 gradation patches, the gradation characteristics in the highlight portion can be adjusted well. The patch groups 1101, 1102, 1103 and 1104 are composed of patches having a resolution of 200 LPI (lines / inch).
1105, 1106, 1107 and 1108 are composed of 400 LPI patches. Note that a patch group having the same tone pattern may be output at two resolutions. However, when tone characteristics greatly differ due to a difference in resolution, it is preferable to set a tone pattern according to the resolution.

Next, the screen shown in FIG. 10D is displayed on the operation panel 300d, the output test print 2 is placed on the platen glass 201, and the "read" key is pressed. The reading of 2 is started. Then, in step S107, the density information output from the LOG conversion unit 304 is stored in the memory together with the laser output level and the position information of the corresponding patch.

At this stage, the gamma characteristic of the printer shown in the third area III of FIG.
In 08, the gamma conversion characteristic of the γ correction unit 312 is set by exchanging the input / output relationship of the obtained gamma characteristic.
When calculating the gamma conversion characteristics, test print 2
Since there is only data for the number of gradation patterns
Insufficient data is supplemented by interpolation processing so that the laser output levels correspond to all levels from to.

Next, the second control in the first automatic gradation correction will be described.

When the development of the latent image is continuously performed, the toner concentration of the developer in the developing device is reduced, and the developing property is reduced.
In addition, a change in the developability also occurs due to a change in the surrounding environment, repetition of the development process, and the like, resulting in a change in image density and gradation reproducibility.

In the present embodiment, as a second control, a test pattern is formed on the photosensitive drum in order to suppress changes in image density and gradation reproducibility and obtain stable density and gradation reproducibility. Then, the image density is detected by an image density sensor 709 (see FIG. 8) provided at a position facing the photosensitive drum, and image density detection control for controlling image density and gradation reproducibility is performed. Further, with respect to chromatic image formation, a toner density sensor installed in each developing unit provides
A developer concentration detection control for detecting and controlling the toner concentration of the developer in the developing device is performed. The image density sensor 709 and the toner density sensor include, for example, a light emitting unit of an LED and a light receiving unit of a photodiode that receives light output from the light emitting unit.

In the present embodiment, in the chromatic color developing step, that is, in the image formation of each YMC color, the signal output by the image density detection control is used for correcting the developer density detection control. Hereinafter, the developer density detection control will be described as an example of Y image formation.

The above-described toner density sensor is provided in the developing unit 230. This toner concentration sensor uses the characteristic that the toner in the two-component developer reflects infrared light and the carrier absorbs infrared light. That is, the developer in the developing device 230 is irradiated with infrared light by the LED, and the amount of infrared light reflected by the developer is detected by the photodiode to calculate the toner concentration of the developer. The image density is controlled by replenishing the toner according to the calculated toner density.

Immediately after the developer is charged into the developing device 230, the amount of reflected light of the developer in a state where the developer is not used is measured by a photodiode, and the output of the photodiode is set to SIG (init-Y). SIG (init-Y) is stored in the memory as a control target value of the toner concentration of the developer.

Next, when the image forming process is started and the use of the developer is started, the output SIG (cal-Y) of the photodiode is measured for the developer at each time when an image is formed. , Difference from SIG (init-Y) stored in memory メ モ リ SIG
Is calculated. △ SIG (Y) = SIG (init-Y)-SIG (cal-Y)… (11)

Equation (11) indicates that the previously measured toner density is 1
The deviation ΔD from the initial value of the toner density at that time is calculated based on the output sensitivity value RATE per weight% change. △ D = △ SIG / RATE… (12)

The amount of toner supplied into the developing unit 230 is determined by the calculated value of the shift amount ΔD. That is, the deviation amount △ D
If the value is minus, the toner corresponding to the deviation amount ΔD is supplied, and if the value ΔD is positive, the supply of the toner is stopped. For example, when △ D is -1% by weight, 1% by weight
A considerable amount of toner is replenished. When ΔD is + 1% by weight, no toner is replenished. In this way, control is performed to maintain the initial toner concentration.

Next, the image density detection control will be described.

The image density detection control is executed at a predetermined timing, and a patch image is formed on the photosensitive drum 217 as a reference image for density detection. That is, a patch image signal having a signal level corresponding to a predetermined density generated by the pattern generator is supplied to the PWM circuit 313.
As a result, a patch electrostatic latent image corresponding to a predetermined density is formed on the photosensitive drum 217, and the patch electrostatic latent image is developed by the developing device 230. Note that the patch density is set to a value at which the development characteristics are most easily controlled. This makes it possible to control not only the image density but also the gradation reproducibility to desired characteristics.

Next, the density of the patch toner image is measured by the image density sensor 709. The measured patch density corresponds to the toner density of the developer in the developing device 230.

More specifically, an image density sensor
Signal S (sig-Y) output from photodiode 709
Is supplied to one input terminal of a differentiator (not shown).
A reference signal S (int-Y) corresponding to a specified density (initial density) of the patch is input to the other input terminal of the differentiator. Therefore, a signal S (cal-Y) indicating the difference between the density of the patch toner image and the initial density, that is, the density difference, is output from the differentiator. The signal S (cal-Y) is supplied to the CPU 300a. This signal S (cal-Y) is used for correcting the toner supply control to the developing device 230 by the developer concentration detection control described above.

Generally, as the toner density of the developer increases, the image density increases, and conversely, the image density at which the toner density of the developer decreases decreases. In addition, changes in development efficiency occur due to environmental fluctuations or deterioration in durability. Therefore,
A constant image density is not guaranteed only by the developer density detection control. Therefore, in the present embodiment, the target value SIG (init-Y) of the developer density detection control is adjusted based on the signal S (cal-Y) indicating the density difference obtained by the image density detection control.

Target value SIG (init-Y) of developer concentration detection control
A specific adjustment method will be described. Assume that the initial toner concentration of the developer is 6% by weight. To perform image density detection control with toner replenished so that the toner density becomes 6% by weight based on the output of the toner density sensor and the patch density is lower than the initial density, and to return to the initial density If it is determined that 5 g of the toner is required, the current toner concentration is considered to be about 1% by weight lower. Therefore, the target value of the developer concentration detection control is changed from 6% by weight to a new target value SIG (tg
tY) is changed to 7% by weight, and thereafter, the developer concentration detection control is performed with the new target value. This makes it possible to maintain the image density at a desired value. Of course, in the developing device of the present embodiment, 5 g of toner corresponds to about 1% by weight, but this value differs for different developing devices.

[Second Automatic Tone Correction] The toner density of the developer is controlled by using the second control in the first automatic tone correction described above, and further, by the patch density formed on the photosensitive drum. By correcting the control target value of the toner density, it is possible to suppress the fluctuation of the developing characteristic and to stably maintain the image density and the tone reproducibility.

However, the image density and gradation reproducibility are not determined only by the development characteristics corrected by the second control. For example, the image density and the gradation reproducibility fluctuate due to various factors such as a change in the light attenuation characteristic of the photosensitive drum, a change in the intensity of the laser beam, and a fluctuation in the mechanical accuracy of the apparatus. Changes in image density and gradation reproducibility due to these factors cannot be absorbed by the above-described first control in the first automatic gradation correction. In other words, when the variation due to the above factors is corrected by the first control, the condition of the second control is changed, so that not only the desired control performance cannot be obtained, but also the amount corrected by the first control. By the second control, the original state is restored, that is, the state is returned to the defective state before the correction.

Therefore, in the present embodiment, the second control is adjusted based on the result of the first control in order to effectively apply the first control and the second control. Below, Y
This control will be specifically described as an example.

The patches in the image density detection control are formed with a predetermined optimum density in order to guarantee the gradation reproducibility. That is, the patch image signal output from the pattern generator is sent to the gamma correction unit 312, where the patch image signal is gamma-converted so as to obtain a desired density, and a patch is formed on the photosensitive drum by the gamma-converted patch image signal.

As described above, the gamma conversion characteristic of the γ correction unit 312 is appropriately changed by the first control. Therefore, the patch density formed on the photosensitive drum is adjusted to a preset optimum density by performing the first control.

Using the newly set gamma conversion characteristic of the gamma correction unit 312, a patch density is detected by forming a patch.
Density difference signal obtained from S (sig-Y) and reference signal S (int-Y)
S (cal-Y) is stored in the memory as the correction value S (adj-Y) of the reference signal, and thereafter, a new reference signal obtained by adding or subtracting the correction value S (adj-Y) from the reference signal S (int-Y) The image density detection control described above is performed using S (aint-Y) as the specified density (initial density) of the patch. This makes it possible to maintain the desired image density and the optimum gradation characteristic corrected by the first control using the image density detection control.

Further, when the first control is performed, the toner concentration of the developer is in the transition period of the control, and converges to the target value SIG (tgt-Y) newly set by the image density detection control. Most are not. Therefore, in the present embodiment, at the same time as performing the first control, the toner density sensor detects the toner density SIG (cal-Y) and replaces it with a new target value SIG (tgt-Y). This makes it possible to maintain the desired image density and the optimum gradation characteristics corrected by the first control using the developer density control.

As described above, in this embodiment,
The image density and the tone reproducibility are controlled by the first control according to the present invention, and the image density and the tone reproducibility are controlled by the second control. Furthermore, based on the result of the first control,
By adjusting the second control, a full-color image can be formed with stable image density and gradation reproducibility.

[PDL] FIG. 15 is a diagram for describing PDL data.

As shown in FIG. 15A, a PDL represented by Adobe PostScript (registered trademark) converts an image of one page into an image description using character codes, an image description using graphic codes, and raster image data. A language for combining and describing elements such as an image description, and data in which an image is described by PDL is PDL data.

FIG. 15 (b) shows a description example using character codes. L100 is a description for designating a character color. Parentheses {} indicate CMYK densities in order from the left. The minimum value is 0.0, and the maximum value is 0.0. Is 1.0. Therefore, the description of L100 specifies the text color as black.

Next, L10l is a description for substituting the character string "IC" into the variable String1, L102 is a description for laying out the character string, and the first and second parameters are the lower left vertex of the rectangular area in which the character string is laid out. The xy coordinates shown, the third parameter is the size of the character, the fourth parameter is the space between the characters, and
The fifth parameter indicates a character string to be laid out. In other words, the description of L102 is the character string "IC" stored in the variable String1 with the coordinates 0.3 and the interval 0.1 from the coordinates (0.0, 0.0).
Is laid out.

FIG. 15C shows a description example using a graphic code. L103 is a description for specifying a line color like L100, and red is specified as the line color. L104 designates drawing a line, the first and second parameters indicate the starting point coordinates of the line, the third and fourth parameters indicate the end coordinates of the line, and the fifth parameter indicates the thickness of the line. That is, the description of L104 is an instruction to draw a line having a thickness of 0.1 from the coordinates (0.9, 0.0) to the coordinates (0.9, 1.0).

FIG. 15D shows a description example using raster image data, and L105 is a description for substituting a raster image for a variable image1. The first parameter of L105 is the image type and the number of color components of the raster image, the second parameter is the number of bits per color component, and the third and fourth parameters are
Each represents the image size in the xy direction. The fifth and subsequent parameters are raster image data. Therefore, the number of raster image data is the product of the number of color components represented by the first parameter and the image size in the xy direction represented by the third and fourth parameters. In the description of L105, CMYK having four color components is designated as the image type, and the image size in the xy direction is 5, so the number of raster image data is 4 × 5 × 5 = 100.

L106 is a description for laying out the raster image data. The first and second parameters are the xy coordinates of the lower left vertex of the rectangular area where the raster image data is laid out, and the third and fourth parameters are the xy coordinates of the rectangular area. size,
The fifth parameter indicates the raster image data to be laid out. That is, the description of L106 is based on the coordinates (0.
(0,0.5) is a variable image in a rectangular area of 0.5 vertically and horizontally with the lower left vertex
This is an instruction to lay out the raster image data stored in 1.

FIG. 16 is a view showing a state in which the PDL data of FIG. 15 is interpreted and developed into raster image data.

R100, R101 and R102 are each shown in FIG.
(b), the PDL data of FIG. 15 (c) and FIG. 15 (d) are developed. These raster image data are actually developed in the DRAM 352 for each CMYK color component.For example, in the part of R100, data of each plane of the CMYK of the DRAM 352 is C = 0, M = 0, Y =
0, K = 255. In the R101 part, the DRAM352 CM
The data of each YK plane is C = 0, M = 255, Y = 255, and K = 0.

Thus, the host computer 101
The PDL data sent from the
The image is expanded into raster image data by 51a and written into the DRAM 352. In the above example, PDL data expanded to CMYK raster image data is described. However, even PDL data expanded to RGB raster image data is interpreted as PDL data and expanded to raster image data. You can also.

[Development of PDL] FIG. 17 is a flowchart showing a control example of the controller 102.
This is executed by the CPU 351a when a print job is instructed from.

First, the interface mode is received from the image forming apparatus 103 in step S11. The interface mode indicates whether RGB data should be sent to the image forming
It indicates whether to send YK data.

Next, in step S12, the host computer 1
One unit of PDL data is received from 01. One unit may be any unit suitable for processing, such as a unit of several bytes, a unit of several lines, or a unit of page.

Next, in step S13, the received PDL data is converted to raster image data, for example, data shown in FIG.
It is determined whether it is L102 of (b), L104 of FIG. 15 (c), and L105 of FIG. 15 (d). Put in. Also,
If the data does not need to be expanded, for example, L100 in FIG. 15 (b), processing such as setting it to an internal variable of RIP is performed in step S15. Note that FIG. 17 illustrates an example in which the processing of steps S13 to S15 is repeated in data units received in step S12. The processing of steps S13 to S15 may be repeated by dividing the received PDL data into processing units.

Next, in step S16, it is determined whether or not the PDL data for one page has been received and expanded, and the processing of steps S12 to S16 is repeated until the PDL data for one page has been received and expanded. . Normally, since the PDL data includes information indicating the end of a page such as an EOF (End of File) code and information instructing the start of printing, the end of the page is determined using these.

If one page of PDL data has been received and expanded, it is determined in step S17 whether the interface mode is the RGB mode or the CMYK mode.
At 18, the RGB image data is sent to the image forming apparatus 103, and in the case of the CMYK mode, the CMYK image data is sent to the image forming apparatus 103 at step S19. Therefore, when the raster image data expanded in the DRAM 352 is different from the format of the image data to be sent to the image forming apparatus 103, the image data read from the DRAM 352 is added to the RGB-CMY
It is necessary to perform K conversion.

The image forming apparatus 103 forms an image for one page based on the image data sent from the controller 102. Note that the RGB image data received by the image forming apparatus 103 is sent to the LOG conversion unit 304 via the external interface 309, and the received CMYK image data is sent to the selector 310 via the external interface 309. .

According to the determination in step S20, the above processing is repeated until the print job is completed.

In the above description, step S1
Although the image data of the format according to the interface mode received from the image forming apparatus 103 is output in 1, the image data indicated by the PDL data transmitted from the host computer 101 from the controller 102 to the image forming apparatus 103 is conversely. The format can be notified, and the interface mode can be adjusted to the format.

[Generation of Judgment Signal TEXT from PDL] The case of developing an image as shown in FIG. 19 described by PDL data as shown in FIG. 18 will be described.

The images described by L100 to L104 in FIG. 18 are the same as the images described by L100 to L104 in FIG. 15, and R100 and R101 shown in FIG. 19 are developed as in FIG. In the description of the figure code by L107 to L108 in FIG. 18, the center position is (0.3, 0.7), the radius is 0.3, and the line width of the contour is
The circle R103 of 0.05 indicates that the outline color is formed in magenta and the inner color is formed in yellow.

FIG. 20 shows an image in which the character portion of the image shown in FIG. 19 and the lines and outlines constituting the figure are extracted. Each pixel of the extracted image shown in FIG. 20, that is, the character portion, and the determination signal TEXT of the pixel corresponding to the line and the contour portion constituting the figure is set to '1', and the determination signals of the other pixels are set to '0'. , And stored in the DRAM 352 as TEXT data. The generation of the TEXT data is performed simultaneously with the expansion of the PDL data. Therefore, when the developed image data is CMYK image data, the DRAM 352 stores a total of 33 bits of 8 bits of CMYK and 1 bit of TEXT data per pixel.

[Line Number Switching by Judgment Signal TEXT] FIG. 21 is a flowchart for explaining the line number switching control by the judgment signal TEXT.
Is a process executed by

In step S21, a line number switching mode is instructed from operation panel 300d. The instruction of the line number switching mode is not always necessary, and the mode set at the time of the previous activation may be used, or the default mode may be used. Further, the number of lines switching mode can be instructed from the host computer 101 via the controller 102 instead of from the operation panel 300d. Also, the number of lines switching mode can be instructed at any time, not only immediately after the power of the image forming apparatus 103 is turned on, but also during the execution of the print job.

The line number switching mode has the following three modes. (1) 200-line fixed mode: A mode in which an image is formed with 200 lines fixed, and is suitable for outputting an image in which an entire page is a photograph. (2) 400-line fixed mode: A mode in which an image is formed with 400 lines fixed, and is suitable for outputting an image in which the entire page is a character or a line drawing. (3) Image area separation switching mode: For each image area, it is determined whether the image included in the area is a character line drawing or a photograph, and the character line drawing area is 400 lines and the photographic area is 200 lines according to the determination result. This mode is suitable for outputting an image in which a character / line image and a photograph are mixed and a determination as to whether the character / line image or the photograph can be made correctly.

In the image area separation switching mode, for each area of the image, it is determined whether or not the image data included in the area indicates a specific value. The area indicating the specific value is 400 lines.
The other area may form an image with 200 lines. In this case, it is suitable for outputting an image in which a character line drawing and a photograph are mixed and the character line drawing has a specific value, for example, a value indicating black.

After the line number switching mode is instructed in step S21, the process waits for a print request command from the controller 102 in step S22. When the print request command is received, the line number switching mode is determined in step S23. In the case of the 200 line fixed mode, the determination signal TE is determined in step S24.
Fix XT to '0' and set 200 lines fixed mode. In the case of the 400-line fixed mode, the determination signal TE is set in step S25.
Fix XT to '1' and set 400 lines fixed mode. In the case of the image area separation switching mode, the image area separation switching mode is set by not fixing the determination signal TEXT in step S26. Then, printing is executed in step S27.

That is, when the image area separation switching mode is set, the memory 108 of the image forming apparatus or the controller 1
The judgment signal TEXT read from the DRAM 352 of 02
And so on. The reading timing of the determination signal TEXT is synchronized with the reading of the image data shown in FIG. If it is difficult to access different addresses in the same memory when reading TEXT data from memory, it is necessary to store the same TEXT data in four memory planes and read the image data for each color at the same time. May be read from the memory plane.

[Automatic Gradation Correction from Controller] The execution of the above-mentioned automatic gradation correction can be instructed from the controller 102. In this case, the test print image is PDL
The points described by the data and the operation
Operation panel (not shown) or host computer 101
However, the processing flow is the same as that in FIG.

FIGS. 22A to 22D show display examples of the operation panel 351d of the controller 102 when the automatic gradation correction is executed from the controller 102, and show the tables of the operation panel 300d of the image forming apparatus 103 shown in FIGS. 10A to 10D, respectively. This corresponds to the example shown.
By displaying the displays corresponding to FIGS. 22A to 22D on the monitor of the host computer 101, the host computer 101 can instruct the execution of the automatic gradation correction.

FIG. 23 is a diagram showing an example of an image of test print 1 when automatic gradation correction is executed from the controller 102. PDL data for forming this test print 1 is described as shown in FIG. . In FIG. 24, square_color () describes the color of the rectangle in CMYK. The first to fourth parameters indicate the color inside the rectangle, and the fifth to eighth parameters indicate the color of the outline of the rectangle. Put_Square
() Describes the layout of the rectangle, where the first and second parameters are the xy coordinates of the lower left vertex of the rectangle, the third and fourth parameters are the xy coordinates of the upper right vertex of the rectangle, and the fifth parameter is the contour The thickness of each is shown.

The PDL data as shown in FIG. 24 is prepared in advance in the ROM 351b of the controller 102, and when the “test print 1” key shown in FIG. 22A is pressed, the PDL data is read from the ROM 351b. After being rasterized by the CPU 351a, it is sent to the image forming apparatus 103. Similarly, PDL data corresponding to test print 2 is also prepared in the ROM 351b in advance, and when the “test print 2” key shown in FIG. 22C is pressed, the PDL data is read from the ROM 351b and rasterized by the CPU 351a. After that, it is sent to the image forming apparatus 103.

The set values of the grid potential Vg and the bias potential Vdc obtained by the automatic tone correction sequence (see step S104 in FIG. 9) are obtained by performing the automatic tone correction by the image forming apparatus 103 alone. The set value is distinguished from the set value and stored in, for example, a RAM with a backup battery or a rewritable nonvolatile memory 1900 (FIG. 25). Similarly,
Automatic gradation correction sequence (see step S108 in FIG. 9)
The LUT indicating the gamma conversion characteristic obtained by the above is distinguished from the set value obtained by performing the automatic gradation correction by the image forming apparatus 103 alone, and the γ correction unit 312 such as a RAM with a backup battery or a rewritable It is stored in a non-volatile memory.

Then, as shown in FIG. 25, the image forming apparatus
103 In the case of image formation by a single unit, that is, in the case of copying machine operation,
Set value of grid potential Vg and bias potential Vdc 1901
And the LUT 1903 for gamma conversion are selected to form an image. Further, in the case of image formation using image data from the controller 102, that is, in the case of a print operation, the set values 1902 of the grid potential Vg and the bias potential Vdc and the LUT 1904 for gamma conversion are selected to form an image. These selections are made according to the control signal C output from the CPU 300a.
ONT ('0' when the copier is operating, '1' when the printer is operating)
It is performed by

[Table Switching by Judgment Signal TEXT] Further, the gamma conversion LUT of the gamma correction unit 312 is selected based on the judgment signal TEXT. That is, as shown in FIG.
The selector 2005 that selects the output of No. 2 receives the determination signal TEXT as a selection signal in addition to the control signal CONT described above. The selector 2005 performs the selection operation 2005a according to these signals. That is, the selector 2005 sets CONT =
When '0' and TEXT = '0', the output of gamma conversion LUT1903a for copier operation and emphasis on gradation is output with CONT = '0' and TEXT
= '1', output of gamma conversion LUT1903b for copy machine operation and resolution emphasis, CONT = '1' and output of gamma conversion LUT1904a for print operation and gradation emphasis when TEXT = '0', When CONT = '1' and TEXT = '1', the output of the gamma conversion LUT 1904b for printing operation and emphasizing resolution is selected.

As shown in FIG. 14, the gamma conversion characteristics of tone emphasis and resolution emphasis are shown in FIG.
When outputting 2, the patch group is obtained by outputting two types of patch groups of 400 lines and 200 lines and reading them. In other words, a 400-line patch group provides a gamma conversion characteristic emphasizing resolution, and a 200-line patch group provides a gamma conversion characteristic emphasizing gradation.

[0145]

[Second Embodiment] An image processing apparatus and method according to a second embodiment of the present invention will be described below. Note that, in the present embodiment, for a configuration substantially similar to that of the first embodiment,
The same reference numerals are given and the detailed description is omitted.

In the present embodiment, in order to suppress changes in image density and tone reproducibility and obtain stable density and tone reproducibility, the first automatic tone correction is performed in the same manner as in the first embodiment. Control. As the second control of the automatic gradation correction, for the formation of a chromatic image, a developer density detection which detects and controls the toner density of the developer in the developing device by a toner density sensor installed in the developing device. Has controls. Further, with respect to black image formation, an image density sensor 709 provided at a position facing the photosensitive drum is provided with an image density detection control for detecting and controlling the density of a test pattern formed on the photosensitive drum. There is also provided a video count control for calculating and controlling a required toner amount from a signal level for each pixel sent from a video counter which is not used.

First, the image density detection control according to the second embodiment will be described.

The image density detection control is started at a predetermined timing, and forms a patch image on the photosensitive drum as a reference image for density detection. The method of forming a patch image is the same as in the first embodiment. The density of the patch image is set to a density at which the development characteristics are most easily controlled. By the control described below, it is possible to control not only the image density but also the gradation reproducibility to desired characteristics.

Next, the actual image density of the patch image is detected using the image density sensor 709. The detected density of the patch image corresponds to the toner density of the developer in the developing device. The output signal S (sig-K) of the image density sensor 709 indicating the density of the patch image is compared with the reference signal S (int-K) to obtain a density difference, and a signal S (cal-K) representing the density difference Is supplied to the CPU 300a. Control for supplying toner to the developing device is performed according to the signal S (cal-K). That is, the signal S (cal-K) is large,
That is, when the density of the patch image is high, the toner is not replenished, and when the signal S (cal-K) is small, that is, when the density of the patch image is low, the toner is replenished according to the value of the signal S (cal-K). This causes the density of the patch image to converge to the target value. As a result, the image density and gradation reproducibility are controlled.

However, the image density detection control can be performed only once every image forming cycle. Therefore, control for continuously forming the same image is required. No. 2
In the embodiment, since it is difficult to apply the developer density detection control using the reflected light to the black developer, the video count control for obtaining the necessary toner amount by integrating the image signal level for each pixel is difficult. Controls the supply of toner to the developing device.

Further, according to the output signal S (sig-K) of the image density sensor 709 in the image density detection control, the conversion gain SUP (gain) of the toner supply amount by the video count control is corrected. That is, when the signal S (sig-K) is small, the density of the patch image is low, and therefore, the toner consumption for the same output level is also small. Therefore, the gain SUP (gain) corresponding to the signal S (sig-K) Is decreased, and conversely, when the signal S (sig-K) is large, the gain SUP (gain) is increased. This allows
It is possible to always supply an optimal amount of toner that matches the toner consumption.

Further, also in the second embodiment, in order to effectively apply the first control and the second control in the automatic gradation correction, the second control is performed based on the result of the first control. Parameters are adjusted. Hereinafter, black image formation will be described.

In the image density detection control, the patch image is output at a predetermined optimum density in order to guarantee the gradation. That is, the patch image signal output from the pattern generator is sent to the γ conversion unit 312, and after the gamma conversion to obtain a desired density,
13 to form a patch image on the photosensitive drum.

The gamma conversion characteristics of the gamma conversion unit 312 are as follows.
As described above, it is appropriately changed by performing the first control. Therefore, the density of the patch image formed on the photosensitive drum is adjusted to the preset optimal density by performing the first control. At this time, a patch image is formed from the patch image signal gamma-converted by the newly set gamma conversion characteristic, a signal S (sig-K) indicating the density of the patch image, and a reference signal S (in
tK) is stored in the memory as a correction value S (adj-K) of the reference signal. Hereafter, the reference signal
Image density detection control is performed using a new correction reference signal S (aint-K) obtained by adding or subtracting a correction value S (adj-K) to S (int-K) as a density target value. As a result, it is possible to maintain the desired image density and the optimal tone reproduction characteristic corrected by the first control using the image density detection control.

Further, when the first control is performed, a new correction reference signal S (aint-K) obtained by adding or subtracting the correction value S (adj-K) to the reference signal S (int-K) is used as the density target. Is set as a value,
The conversion gain SUP (gain) of the video count control is returned to the initial value. This makes it possible to maintain the desired image density and the optimum tone reproduction characteristic corrected by the first control using the developer density control.

As described above, also in the second embodiment, the image density and the tone reproducibility are controlled by the first control according to the present invention, and the image density and the tone reproducibility are controlled by the second control. . Further, by adjusting the second control based on the result of the first control, a full-color image can be formed with stable image density and gradation reproducibility.

As described above, the first aspect of the present invention
According to the second embodiment, a constant density pattern of a plurality of colors and a gradation pattern of a plurality of colors are formed on recording paper, and a contrast voltage and gradation control for gradation control are performed based on a signal obtained by reading the density pattern and the gradation pattern. The first control, which controls the image density and tone reproduction characteristics of the output image by correcting the conversion characteristics, forms a reference density pattern for each color on the photoreceptor, and detects the reflected light from the reference density pattern. By setting the density of the reference pattern to be a target value of the toner density control for controlling the toner density by supplying toner based on the result of detecting the toner density in the developer of each color, the image density and the image density are improved. And second control for controlling the tone reproduction characteristic. Therefore, by adjusting the target value of the density of the reference pattern on the photoreceptor and / or the target value of the toner density control based on the first control result, the short-term and long-term image density and gradation can be adjusted. Variations in reproducibility and other variations in image density and tone reproducibility can be corrected, so that the density and tone reproducibility of copy images and print images can be unified.

Further, since tone correction according to the attribute signal (judgment signal TEXT) can be performed for each copying machine operation and printing operation, it is possible to reproduce image density and gradation more faithfully. become.

[0159]

[Third Embodiment] Hereinafter, an image processing apparatus and a method thereof according to a second embodiment of the present invention will be described. Note that, in the present embodiment, for a configuration substantially similar to that of the first embodiment,
The same reference numerals are given and the detailed description is omitted.

The automatic gradation correction from the controller 102 according to the third embodiment will be described below.

FIG. 27 is a flowchart showing an example of the processing procedure of the automatic gradation correction from the controller 102. The display example of the operation panel 351d is the same as in the first embodiment,
It is shown in FIGS. 22A to 22D. Also,

First, in step S200, unlike the automatic gradation correction in the operation of the copying machine, the conversion table of the γ correction unit 312 is switched to a through-pass table that outputs the input signal as it is. Here, the reason for switching to the through-pass table is to allow the controller 102 to perform all gradation corrections.
If the gamma conversion is performed twice in both of the γ correction table of the correction unit 312, there is a possibility that the color of a dark part is lost and the gradation of a highlight part is skipped. Therefore, if those problems are trivial enough to be ignored, there is no need to switch to the through path table. It should be noted that a through-pass table is also used in the print processing from the controller 102, as in the automatic gradation correction.

Steps S201 to S207 are the same as those in the first embodiment, and a detailed description thereof will be omitted. The optimization process of the correction coefficient in step S203 and the
Since the setting process of the grid potential Vg and the bias potential Vdc in S204 can be approximately replaced with the values described in the above-described “first automatic tone correction” and “second automatic tone correction”, If the sequences of “first automatic gradation correction” and “second automatic gradation correction” are performed first, the processing of steps S201 to S204 can be omitted as in the flowchart shown in FIG.

The RGB image data obtained from the test print 2 is stored in the DRAM 352 and is converted into CMYK image data. In step S208, the CPU 351a samples some points of each patch group of the test print 2 shown in FIG. 14, averages the sampled image data, and then obtains the sampled image data as shown in FIG. From the characteristic curve R
Ask for. Then, the gamma conversion characteristic is set so that the ideal characteristic (linear characteristic) L is obtained. The gamma conversion characteristic for converting the curve R into the straight line L is a curve as shown in FIG. 29 (b), and the table corresponding to this curve is the controller.
The gamma conversion table 201 is stored in the hard disk 354 or the like. The gamma conversion table stored in the hard disk 354 is loaded from the hard disk 354 to the RAM 351c when the power of the controller 102 is turned on. CPU351a
Performs gamma correction on image data to be sent to the image forming apparatus 103 using the gamma correction table loaded in the RAM 351c.
Accordingly, the calibrated image data is sent from the controller 102 to the image forming apparatus 103.

As described above, according to this embodiment, the same effects as those of the first and second embodiments can be obtained, and the reader / scanner attached to the color copying machine can be used without using an expensive densitometer. By using the above, it is possible to perform calibration suitable for the image forming system.

[0166]

[Modification] In the scanning operation of each embodiment described above, the image forming apparatus 103 can output CMYK image data. FIG. 30 shows a configuration example of the image forming apparatus in that case. In FIG. 30, at the time of the scanning operation, the RGB image data read from the original by the scanner unit is converted into CMY image data by the LOG conversion unit 304, and then input to the memory 108, and the masking / UCR unit 308 After being converted to CMYK image data, the selector 310 and the external interface unit 309
Through the controller 102.

At this time, the compression circuit 305 in the configuration shown in FIG.
And the decompression circuit 307 are omitted, but data may be compressed using a lossless compression method. Further, in FIG. 30, in consideration of compatibility with the copying machine operation, the configuration is such that the memory is temporarily stored in the memory 108 even in the scanning operation.
The CMY data after the OG conversion may be directly input to the masking / UCR unit 308.

[0168]

[Other Embodiments] Even if the present invention is applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), an apparatus (for example, a copying machine) Machine, facsimile machine, etc.).

Further, an object of the present invention is to supply a storage medium in which a program code of software for realizing the functions of the above-described embodiments is recorded to a system or an apparatus, and to provide a computer (or CPU or MPU) of the system or the apparatus.
Needless to say, this can also be achieved by the PU) reading and executing the program code stored in the storage medium. In this case, the program code itself read from the storage medium implements the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention. When the computer executes the readout program code, not only the functions of the above-described embodiments are realized, but also the OS running on the computer based on the instructions of the program code.
It goes without saying that an (operating system) performs a part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written into a memory provided in a function expansion card inserted into the computer or a function expansion unit connected to the computer, based on the instruction of the program code, It goes without saying that the CPU included in the function expansion card or the function expansion unit performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

[0171]

As described above, according to the present invention, short-term and long-term fluctuations in image density and gradation reproducibility can be controlled by forming a copy image by the operation of the image forming apparatus alone and by sending it from an external device. It is possible to provide an image processing apparatus and method capable of uniformly correcting a print image based on incoming image data.

Further, it is possible to provide an image processing apparatus and method capable of performing image adjustment suitable for the image forming system at low cost by using the image reading means of the image forming apparatus.

Further, it is possible to provide an image processing apparatus for performing image adjustment suitable for a connected image forming apparatus and a method thereof.

[Brief description of the drawings]

FIG. 1 is an overview diagram showing a configuration example of an image processing system according to an embodiment of the present invention;

FIG. 2 is a schematic diagram illustrating a configuration example of the image forming apparatus illustrated in FIG. 1;

FIG. 3 is a block diagram showing an image processing unit of the image processing system shown in FIG. 1;

FIG. 4 is a timing chart showing image data write and read timings of a memory 108 shown in FIG. 3;

FIG. 5 is a diagram for explaining a determination signal TEXT;

FIG. 6 is a block diagram showing a configuration example of a PWM circuit 313 shown in FIG. 3;

FIG. 7 is a diagram showing a state of pulse width modulation;

FIG. 8 is a diagram illustrating a detailed configuration example of an image forming unit;

FIG. 9 is a flowchart showing a first control example in the first automatic gradation correction;

FIG. 10A is a display example of an operation panel of the image forming apparatus;

FIG. 10B is a display example of an operation panel of the image forming apparatus;

FIG. 10C is a display example of an operation panel of the image forming apparatus;

FIG. 10D is a display example of an operation panel of the image forming apparatus;

FIG. 11 is a diagram showing an example of a test print 1.

FIG. 12A is a view for explaining a method of correcting the maximum density from density information,

FIG. 12B is a diagram for explaining a method of correcting the maximum density from the density information.

FIG. 13 is a characteristic conversion chart showing an example of a density reproduction characteristic,

FIG. 14 is a diagram showing an example of a test print 2;

FIG. 15 is a diagram for explaining PDL data;

FIG. 16 is a diagram showing a state in which the PDL data of FIG. 15 is interpreted and developed into raster image data;

17 is a flowchart showing a control example of the controller shown in FIG. 3,

FIG. 18 is a diagram showing an example of PDL data.

FIG. 19 is a diagram showing an image represented by the PDL data shown in FIG. 18,

FIG. 20 is a diagram showing an image in which a character portion of the image of FIG. 19 and lines and contours constituting a figure are extracted;

FIG. 21 is a flowchart for explaining switching control of the number of lines based on a determination signal TEXT;

FIG. 22A is a diagram showing a display example of an operation panel of the controller when performing automatic gradation correction from the controller;

FIG. 22B is a diagram showing a display example of an operation panel of the controller when performing automatic gradation correction from the controller;

FIG. 22C is a diagram showing a display example of the operation panel of the controller when performing automatic gradation correction from the controller;

FIG. 22D is a diagram showing a display example of the operation panel of the controller when performing automatic gradation correction from the controller;

FIG. 23 is a diagram showing an example of an image of a test print 1 when an automatic gradation correction is executed from the controller 102;

FIG. 24 is a diagram showing PDL data for forming a test print 1.

FIG. 25 is a diagram showing a memory and a table in which data obtained by automatic gradation correction is stored;

FIG. 26 is a diagram for explaining switching of a gamma conversion table based on a determination signal TEXT;

FIG. 27 is a flowchart illustrating an example of a processing procedure of automatic gradation correction from a controller according to the third embodiment of the present invention;

FIG. 28 is a flowchart illustrating another example of the processing procedure of the automatic gradation correction from the controller according to the third embodiment;

FIG. 29 is a view for explaining a method of generating a gamma conversion table set in the controller according to the third embodiment;

FIG. 30 is a block diagram illustrating a modified example of the image processing unit of each embodiment according to the present invention.

Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI G06T 5/00 G06F 15/68 310A

Claims (36)

[Claims] A first generation unit configured to generate a first image signal from a document image; a second generation unit configured to generate a second image signal from image data described in a page description language; Correction means for correcting the first or second image signal; forming means for forming a visible image on a recording medium based on the image signal corrected by the correction means; image signal generated by the first generation means A first setting unit for setting a correction process of the correction unit and an image forming condition of the forming unit in image formation based on the first image signal, and an image signal generated by the second generation unit And a second setting unit for setting an image forming condition of the forming unit and a correcting process in the image forming based on the second image signal. Location. 2. The image processing apparatus according to claim 1, wherein the first and second setting units include density information of the first pattern based on an image signal generated by the first generating unit from the first pattern formed by the forming unit. The image forming condition of the forming unit is set based on the detected density information of the first pattern, and the image forming condition is generated by the first generating unit from the second pattern formed by the forming unit. The density information of the second pattern is detected based on the detected image signal, and a correction process of the correction unit is set based on the density information of the detected second pattern. Image processing device. 3. The method according to claim 2, wherein the density of the first pattern is detected by the first generating means, and the density of the second pattern is detected by the second generating means. The described image processing device. 4. The image processing apparatus according to claim 1, wherein the second pattern includes a plurality of patterns according to an attribute of the image, and the first and second setting units perform a plurality of correction processes according to the attribute of the image to the correcting unit. 3. The image processing apparatus according to claim 2, wherein the setting is performed. 5. The correction means has a plurality of tables respectively corresponding to the plurality of correction processes, and a table selected based on an attribute signal supplied together with an image signal from the first and second generation means. 5. The image processing apparatus according to claim 4, wherein the image signal is corrected by using the image signal. 6. The density of the recording material of the forming means is detected, and the density of a third pattern formed on the image carrier of the forming means is detected. 6. The image processing apparatus according to claim 1, further comprising control means for controlling the density of the recording material based on the density of the third pattern. 7. A control target value in said control means is adjusted based on an image forming condition of said forming means by said first and second setting means and a result of setting of correction processing by said correction means. 7. The image processing device according to claim 6, wherein: 8. The printing apparatus according to claim 5, wherein the control unit further controls the density of the recording material based on a result of integrating the levels of the image signals supplied to the forming unit. An image processing apparatus according to claim 1. 9. The image forming condition of the forming unit set by the first and second setting units is a contrast potential of an image carrier.
The image processing device according to any one of claims 1 to 8. 10. The method according to claim 1, wherein the correction processing of the correction means set by the first and second setting means is a gamma conversion processing. Image processing device. 11. The apparatus according to claim 2, further comprising a pattern generator configured to generate an image signal corresponding to the first and second patterns formed by the first setting unit. Image processing device. 12. The image processing apparatus according to claim 11, further comprising storage means for storing image data written in a page description language corresponding to said first and second patterns to be formed by said second setting means. 3. The image processing device according to claim 2, wherein 13. The image data described in a page description language corresponding to the first and second patterns stored in the storage unit is developed into an image signal by the second generation unit. 13. The image processing device according to claim 12, wherein 14. A first generating means for generating a first image signal from a document image, a first correcting means for correcting the first image signal, and a first correcting means for correcting a first image signal from image data described in a page description language. A second generating unit that generates a second image signal; a second correcting unit that corrects the second image signal; and a recording medium based on the image signal corrected by the first or second correcting unit. Forming means for forming a visible image, based on an image signal generated by the first generating means, a correction process of the first correcting means in image formation based on the first image signal, and A first setting unit for setting an image forming condition; a correction process of the second correction unit in image formation based on the second image signal based on an image signal generated by the second generation unit; and Forming means And a second setting unit for setting the image forming conditions. 15. The first and second setting means, based on an image signal generated by the first generating means from a first pattern formed by the forming means, density information of the first pattern. The image forming condition of the forming unit is set based on the detected density information of the first pattern, and the image forming condition is generated by the first generating unit from the second pattern formed by the forming unit. Detecting density information of the second pattern based on the detected image signal, and setting a correction process of the first or second correction unit based on the detected density information of the second pattern. 15. The image processing device according to claim 14, wherein: 16. The second pattern includes a plurality of patterns according to an attribute of an image, and the first and second setting means perform a plurality of correction processes according to the attribute of the image on the first and second sets. 16. The image processing apparatus according to claim 15, wherein the image processing apparatus is set to a second correction unit. 17. The first and second correction means have a plurality of tables respectively corresponding to the plurality of correction processes, and the attribute signal supplied together with the image signal from the first or second generation means. 17. The image processing apparatus according to claim 16, wherein the image signal is corrected using a table selected based on the image signal. 18. A method for detecting the density of a recording material of the forming unit, detecting the density of a third pattern formed on an image carrier of the forming unit, and detecting the detected density of the recording material. 18. The image processing apparatus according to claim 14, further comprising control means for controlling the density of the recording material based on the density of the third pattern. 19. A control target value in said control means is adjusted based on an image forming condition of said forming means by said first and second setting means and a result of setting of correction processing by said correction means. 19. The image processing device according to claim 18, wherein: 20. The recording medium according to claim 18, wherein the control unit further controls the density of the recording material based on a result of integrating the levels of the image signals supplied to the forming unit. An image processing apparatus according to claim 1. 21. An image forming condition set by said first and second setting means, said image forming condition being a contrast potential of an image carrier.
The image processing device according to any one of claims 14 to 20. 22. The method according to claim 14, wherein the correction processing of the first and second correction means set by the first and second setting means is a gamma conversion processing. An image processing device according to any one of the above. 23. The apparatus according to claim 15, further comprising a pattern generator configured to generate an image signal corresponding to the first and second patterns to be formed by the first setting unit. Image processing device. 24. The image processing apparatus according to claim 24, further comprising storage means for storing image data described in a page description language corresponding to said first and second patterns to be formed by said forming means. 16. The image processing device according to claim 15, wherein 25. The image data described in a page description language corresponding to the first and second patterns stored in the storage unit, is developed into an image signal by the second generation unit. The image processing device according to claim 24, wherein: 26. A first generating step of generating a first image signal from a document image using image reading means, and a second generating step of generating a second image signal from image data described in a page description language. A generating step; a correcting step of correcting the first or second image signal; a forming step of forming a visible image on a recording medium based on the image signal corrected by the correcting means; Based on the image signal
A first setting step of setting a correction process of the correction step and an image forming condition of the forming step in image formation based on the first image signal; and an image signal generated from image data described in a page description language. And a second setting step of setting an image forming condition of the forming step in image forming based on the second image signal. 27. The first and second setting steps include detecting density information of the first pattern based on an image signal generated by the image reading means from the first pattern formed in the forming step. Setting image forming conditions of the forming step based on the detected density information of the first pattern, and setting the image forming condition based on an image signal generated by the image reading unit from the second pattern formed in the forming step. 27. The image processing method according to claim 26, wherein density information of a second pattern is detected, and a correction process of the correction step is set based on the detected density information of the second pattern. 28. A first generating step for generating a first image signal from a document image using an image reading means, a first correcting step for correcting the first image signal, and a description in a page description language. A second generation step of generating a second image signal from the obtained image data, a second correction step of correcting the second image signal, and an image corrected in the first or second correction step A forming step of forming a visible image on a recording medium based on the signal, and an image signal generated by the pattern generating means.
A first setting step of setting an image forming condition of the first correction step and an image forming condition of the forming step in image formation based on the first image signal; and generating the image data from image data described in a page description language. And a second setting step of setting image forming conditions of the second correcting step and image forming conditions of the forming step in image formation based on the second image signal based on the second image signal. Image processing method. 29. The first and second setting steps include detecting density information of the first pattern based on an image signal generated by the image reading unit from the first pattern formed in the forming step. Setting image forming conditions of the forming step based on the detected density information of the first pattern, and setting the image forming condition based on an image signal generated by the image reading unit from the second pattern formed in the forming step. The density information of a second pattern is detected, and a correction process of the first or second correction step is set based on the density information of the detected second pattern.
28. The image processing method according to 28. 30. A recording medium on which a program code for image processing is recorded, wherein a code of a first generation step of generating a first image signal from a document image using an image reading means, and a page description language. Code of a second generation step of generating a second image signal from the described image data, code of a correction step of correcting the first or second image signal, and an image signal corrected by the correction unit Based on a code of a forming step of forming a visible image on a recording medium based on the image signal generated by the pattern generating means,
It is generated from a code of a first setting step for setting a correction process of the correction step and an image forming condition of the forming step in image formation based on the first image signal, and image data described in a page description language. A recording medium comprising: a correction process in the correction step in image formation based on the second image signal based on an image signal; and a code in a second setting step for setting an image forming condition in the formation step. . 31. A recording medium on which a program code for image processing is recorded, wherein: a code of a first generation step of generating a first image signal from a document image by using an image reading means; A code for a first correction step for correcting an image signal, a code for a second generation step for generating a second image signal from image data described in a page description language, and correcting the second image signal Code of a second correction step, code of a formation step of forming a visible image on a recording medium based on the image signal corrected in the first or second correction step, and an image signal generated by the pattern generation unit Based on
A code of a first setting step for setting an image forming condition of the first correction step and an image forming condition of the first correction step in the image formation based on the first image signal, and image data described in a page description language. A code of a second setting step of setting a correction process of the second correction step and an image forming condition of the forming step in image formation based on the second image signal based on the generated image signal. An image processing method characterized by the following. 32. An input means for inputting image data expressed in a page description language, and performing correction processing on the image data using correction data;
Generating means for generating raster data; output means for outputting the raster data to a printer; and patch detection data indicating an image formed based on the reference patch data, outputting reference patch data indicating a reference patch to the printer. And a creation unit for creating the correction data by inputting the correction data from the printer. 33. An image processing apparatus connected to a color copying machine having a calibration processing mode for a color copy mode and a calibration processing mode for a color print mode, wherein the calibration is performed on the color copying machine. An image processing apparatus comprising: an output unit that outputs an instruction command for instructing execution of an application process. 34. The color copier according to claim 33, further comprising a storage unit for storing image forming conditions and color processing conditions generated in each of the calibration processing modes. Image processing device. 35. An image processing apparatus which receives image data expressed in a page description language, performs correction processing on the image data using correction data to generate raster data, and outputs the raster data to a printer. A processing method, comprising: outputting reference patch data indicating a reference patch to the printer; inputting patch detection data indicating an image formed based on the reference patch data from the printer; and performing the correction based on the patch detection data. An image processing method comprising creating data. 36. An image processing method for an image processing apparatus connected to a color copying machine having a calibration processing mode for a color copy mode and a calibration processing mode for a color print mode, wherein the color copying machine And outputting an instruction command for instructing execution of calibration processing to the image processing apparatus.